1. Field of the Invention
The invention relates to a connection element for attaching of removable dentures at tooth crowns or tooth implants with the locking bar supported slidable perpendicular to the pullout direction of the denture, wherein the locking bar with its effective parts for the locking is guidable under regions of a fixedly positioned element formed at one or several tooth crowns or, to respectively, one or several tooth implants by the force of one or several springs as seen from the pullout direction of the denture and the locking bar is removable again from these regions by actuating of a pushbutton operating onto the locking bar with its parts effective for the bolting against this spring force.
2. Brief Description of the Background of the Invention Including Prior Art
Either active or passive connection elements are employed for attaching removable dentures at crowned teeth or tooth implants. In case of active elements the denture is connected to the tooth crown or the tooth implant by frictional engagement or by locking. The frictional force or the spring force has to be overcome in case of a removal of the denture. The active connection elements are associated with the disadvantage that the frictional force based on the wear for the spring force based on the spring fatigue can decrease in the course of time such that the attachment of the denture is not any longer assured. In addition, periodontal weak residual teeth or implants can be damaged in case the pull-out force of the denture is not precisely defined. Passive connection elements avoid the disadvantages. Here the support of the denture is accomplished by a pure shape matching with the locking bar device.
According to the state-of-the-art today in most cases still the conventional dental technological locking barsxe2x80x94hasp, sliding bolt and plug bar or, respectively, dead bolt are employed. The opening of the locking bars is performed in most cases by having the patient grip into a groove with a fingernail. The manual skill required for this however is not present with each patient. As special shape of a dead bolt represents a conventional construction, wherein the opening of the bolt is performed with a key, wherein the key is entered into a bore hole provided for this purpose.
For alleviation of the handling there have been proposed also so-called semi automatic locking bars, wherein the locking bar is opened by actuating of a pushbutton against the force of a spring. Such a semi automatic locking bar is described for example in the German printed patent document DE 3720623 A1. These semi automatic locking bars however are associated with the disadvantage that the pushbutton has to remain pressed down, which again can cause manual difficulties.
There are also so-called fully automatic locking bars known, which further alleviate the operation. In the known constructions of such locking bars, a locking element acting perpendicular to the direction of motion of the locking bar and formed as a leaf spring or as a spring plate loaded with an additional helical spring engages into a recess at the cylindrically shape locking bar axis from the closing direction after operating of the spring loaded pushbutton and retains the locking bar axis such that the pushbutton can be released for removal of the denture. The locking element supports itself thereby at the limit at a of the fixedly seated part, such that upon engaging and locking simultaneously the denture is slightly lifted. The locking element pushes again against this limit stops upon insertion of the denture and the locking element is thereby returned in its position, whereby the axis of the locking bar is released again.
On the one hand the high construction requirements based on the additional spring are a disadvantage in the solutions. On the other hand the locking mechanism is subject to interferences. If the denture is not seated completely free of friction at the fixedly seated part and the force of the second spring is insufficient to overcome this friction, then the locking mechanism fails.
A fully automatic bolting device has been proposed by the applicant in the German patent DE 197 28 863 C2, wherein a locking device is provided movably supported in the pushbutton or, respectively locking bar or in the casing, wherein the locking device releases the locking bar not upon insertion of the denture, as in case of the other fully automatic locking bars, but already upon removal of the denture. The described susceptibility to interference of the other fully automatic locking bars could thereby be eliminated. The expensive production of the locking bar device proved however to be a disadvantage.
1. Purpose of the Invention
It is the object of the present invention to generate an easily operatable denture attachment formed as a fully automatic locking bar, wherein the denture attachment operates without problems even in case of increased friction between removable denture and fixedly disposed part and which requires a comparatively small production expenditure.
2. Brief Description of the Invention
This object is accomplished by the connection element with the features of claim 1. The subclaims contain advantageous further embodiments of the connection element according to the present invention. In principle the known idea of a movably supported locking device from the German patent DE 197 28 863 C2 is taken up again with the present invention, wherein the locking device is placed into motion upon actuating of a pushbutton by the cooperation of limit stop and control faces. However the function of the locking device is here associated within easy lifting of the denture in contrast to the construction forms described in the German patent and similar as in case of the other fully automatic locking bars having become known. This spring force or the motion of a locking bar is deflected by way of limit stop and guide faces upon actuating of the pushbutton against the force of one or several springs such that the locking device moves. This motion in turn effects a slight lifting of the denture in pullout direction without limit stop at the fixedly seated part. Furthermore, the spring force can be deflected by limit stop and guide faces such that the spring force supports the denture in this slightly elevated position. This leads to constructions, wherein the release of the locking bar by the locking device does not occur during the removal of the denture as in case of the solutions of the German patent DE 197 28 863 C2, but only upon the insertion of the denture. The locking device retains the locking bar fixed against the force of the spring by the coaction of further limit stop faces. The same limit stop faces, which limit stop faces effect the lifting of the denture during the removal, effect the seating back of the locking device, wherein the locking device now again releases the locking bar. The spring can now return the locking bar such that the locking knowledge becomes effective.
Furthermore, modifications are possible, wherein in fact the locking device effects the lifting of the denture upon pressing of the pushbutton, wherein however the locking device is not held fixed itself. The locking bar nevertheless is initially however locked: based on the slight lifting of the denture the locking bar cannot any longer be led back into the corresponding undercut. The locking bar is the led back upon removal of the denture as in the constructions known from the German patent DE 19728863 C2, such that inclined faces have to be provided as described there, which inclined faces lead the locking bar against the force of the spring upon insertion of the denture.
A plurality of constructive solutions are conceivable for realizing the idea. Only several of the constructive possibilities are illustrated with reference to the drawings in more detail in the following. The individual elements presented in connection with the various described constructive possibilities can also be combined with each other.